One of the most common railroad track maintenance functions is the replacement of old cross ties beneath the rails of a railroad track and the rebuilding of the ballast about the crossties. One procedure in the replacement of railroad crossties is to cut the ties across their lengths at a position between the rails of the track and force the halfs or "butts" of the crossties laterally out from beneath the rails. The space previously occupied by the old crosstie is then filled with a new crosstie and the ballast about the crosstie is repaired. As the work progresses, a trail of crosstie butts are left behind on both sides of the railroad track.
The crosstie butts and other objects strewn about the railroad tracks must be removed. In the past, manual labor has been required to hoist the tie butts to a load carrying vehicle mounted on the railroad tracks, and after the vehicle was loaded, the vehicle was moved to a dump location where its load was removed for disposal, etc. More recently, automated equipment has been substituted for the manual workers and included, for example, one self-propelled vehicle mounted on and movable along the rails of the railroad track and which included a crane or other loading device for mechanically grasping and loading the tie butts and another self-propelled load carrying vehicle mounted on and movable along the rails which followed the loading vehicle and received the tie butts and transported the tie butts to a removal area. While this procedure has reduced the number of people required to perform the desired function, it still requires at least two operators and two vehicles.
Various self-propelled load carrying vehicles have been developed in the past which can travel over a flat road surface and which also can travel on railroad tracks. Some of the prior art vehicles have included conventional road wheels, with the rear wheels being the driving wheels and the front wheels being the steerable wheels, and railroad wheels are attached to the vehicle for railroad track travel. In some instances the railroad wheels are retractable and distensable so that the vehicle can be driven on its road wheels to the railroad track, and the railroad wheels lowered down into engagment with the railroad track to support the vehicle from the railroad track. Usually the driving wheels at the rear of the vehicle are constructed so that the space between the rear wheels corresponds to the space between the rails of the railroad track, and the road driving wheels engage the rails and are used to propel and brake the vehicle as it moves along the rails. These prior art vehicles are usable for various maintenance jobs along railroad tracks. An example of a vehicle having both road wheels and railroad wheels is shown in U.S. Pat. No. 3,874,306.
The prior art also discloses self-propelled load carrying dump vehicles or "dump trucks" wherein the load carrying body is tiltable about an approximately horizontal axis so that the load can be dumped from the dump body through its rear opening, and wherein the dump body can rotate about an approximately upright axis so that the dump opening can be directed to the side of the vehicle as the load is being dumped. Examples of this type structure are disclosed in U.S. Pat. Nos. 1,432,328, 1,970,627 and 2,174,956. Vehicles of this type, wherein the dump body is not only tiltable but is also rotatable, are not generally available, apparently because the structure necessary for rotating the dumpbody requires additional expense and maintenance, and because the vehicle can be turned on its road support wheels to direct the rear of the vehicle toward the area where it is desired to dump the load.
The prior art also discloses a load bearing vehicle mounted on railroad wheels for use only along railroad tracks, wherein the load bearing body is tiltable and rotatable so that the load can be dumped to the side of the railroad track while the vehicle is mounted on and aligned with the railroad track. An example of this type structure is found in U.S. Pat. No. 1,055,575.
The prior art also discloses many self-propelled load bearing vehicles that include a crane, winch or other loading means mounted on the vehicle for placing a load on and/or removing a load from the vehicle.
The prior art does not seem to disclose a self-propelled load carrying vehicle having road wheels and retractable railroad wheels and a rotary dump, together with a crane or other loading means for loading the dump and a conveyor means for displacing the load from the dump beyond the dump opening, far out to the side of the vehicle beyond the railroad tracks which support the vehicle.